This invention relates to produce sizers, and more particularly to a sizing apparatus which employs a plurality of screw transport conveyors each associated with an adjustable sizing plate and an opening therebetween arranged to permit selected sizes of produce to fall therethrough while larger sized produce, greater in diameter than the opening, is moved by the screw conveyor to it's outfeed end.
A produce sizer functions to separate a produce, for example onions, apples, oranges, peaches and the like into a plurality of sizes for packaging and marketing. All known types of produce sizers available heretofore suffer from structural limitations which tend to reduce their efficiency in accomplishing adequate separation of produce into size categories based on the smallest diameter of the produce. They also tend to scuff, abrade and otherwise damage the produce during the sizing operation. Such types of sizers are exemplified by U.S. Pat. Nos. 430,031; 1,655,422; 1,661,501; 3,329,263; and 3,451,084.
Briefly, U.S. Pat. No. 430,031 discloses a machine for sorting or sizing fruits and vegetables by passing the produce forwardly across an elongated space of progressively increasing sizes of rectangles formed between a fixed member and a rotary member, and in collecting the produce that drops through the first available corresponding size stage. The sizing surfaces of the rotary member and the cooperating fixed member are linear in configuration, and, since the sizing stages are formed integrally with each other, adjustment of each sizing stage without affecting the size opening of each other size stage is impossible. U.S. Pat. Nos. 1,655,422 discloses apparatus utilizing separating structure generally similar to that taught in U.S. Pat. No. 430,031.
U.S. Pat. No. 1,661,501 discloses a separating or classifying machine which is most typical of conventional grading equipment commonly found in the marketplace. A plurality of rollers are rotated in the same direction so that produce is lifted by one roller and forced downward by the other during the classifying operation. This construction has been found undesirable in its damaging effects on the produce.
U.S. Pat. No. 3,329,263 teaches that the rotation of rolls 40 and 41 relative to the intermediate partition 33 is such as to lift the root crop upward to help dislodge clinging material while moving the produce toward the outlet end and simultaneously allowing the escape of stones, mud and other debris. This device does not function to classify or size produce in any manner.